Pathology: What Causes Inflammation And Why It Occurs

Surely, inflammation is half a billion years old, since even the lowly starfish may experience it. Virtually every human being who ever lived has suffered from it, perhaps dozens or hundreds of times. But why? And what is it? Pathology textbooks take refuge in rolling Latin, describing inflammation by its signs: rubor, calor, tumor, dolor (redness, heat, swelling, pain). It is the reaction of a part or all of the body to injury. In its later stages it includes the processes needed to repair the injury.

Clearly, such a universal phenomenon should have commanded intensive research attention. In fact it has not, and until recently there has been so little research that 90% or more of today's knowledge about inflammation has been gained in the past ten years. Not until a fortnight ago did the International Inflammation Club convene its first symposium. The club is an amorphous group with no officers or formal organization. Conceived by Biochemist John C. Houck of Children's Hospital in Washington, D.C., it drew together 80 researchers as guests of the Upjohn Co. at Brook Lodge in Michigan.

Total Mobilization. Some of them had interests so specialized that even other scientists could not understand their presentations. Houck had expected this. He had wanted the meeting to build bridges of communication between men who had never heard of one another's work, and that it did. And the scientists concurred on some basic aspects of the subject that will be important in the treatment of patients—some, admittedly, in the distant future, but others perhaps immediately.

Inflammation, all agreed, is one of nature's most basic defenses against injury. As such, Dr. Houck pointed out, it has to be enormously versatile because the injury may be a stabbing or abrasive wound, a burn, or invasion by infectious microbes. Even a sterile, uninfected wound summons inflammation to its aid. Since nature cannot construct individual defenses against an infinite variety of attacks from innumerable sources, said the Upjohn Co.'s Dr. E. Myles Glenn, it mobilizes everything at hand—the immune and clotting mechanisms, the blood-forming and lymph systems, the liver, and many others. Sometimes it overreacts to the injury; sometimes it damages the very system it is seeking to defend, as in autoimmune diseases.

"We visualize the overall inflammatory process," said Dr. Glenn, "as a wave or chain of cellular destruction." The first result of injury is to cut cells open, in the case of a stab wound or burn, or to weaken their membranes, in the case of many infections or poisoning by plants or animals. Either way, powerful chemicals that had been locked inside the cells, some in leakproof packages, spill out.